1. Field
The present disclosure relates to a thin film transistor, and a flat panel display device, such as an organic light-emitting display device or a liquid crystal display device including the thin film transistor.
2. Description of the Related Technology
In general, flat panel display devices, such as organic light-emitting display devices or liquid crystal display devices, include thin film transistors (TFTs) and pixel units that are driven by the TFTs and display an image.
A TFT generally has a structure in which a gate electrode, an active layer, and source and drain electrodes are stacked on a substrate. Accordingly, when a current is applied to the gate electrode through a circuit installed in the substrate, the current is applied to the source and drain electrodes via the active layer, and the current is applied to a pixel electrode of a pixel unit connected to the source or drain electrode at the same time.
The pixel unit generally includes the pixel electrode, an opposite electrode facing the pixel electrode, and an emission operating layer interposed between the pixel electrode and the opposite electrode. If the device is an organic light-emitting display device, the emission operating layer may be an organic emission layer for self-emitting light. If the device is a liquid crystal display device, the emission operating layer may be a liquid crystal layer that selectively allows backlight to pass therethrough.
In such devices, when a current is applied to the pixel electrode through the TFT as described above, an optimal voltage is formed between the pixel electrode and the opposite electrode. Thus, emission occurs in the emission operating layer, thereby displaying an image.